PHYS 1007 Lecture Notes - Lecture 15: Moment Of Inertia, Momentum, Kinematics
9 Apr 2016
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Rotaional kineic energy: ke = mr2w2 = iw2. Review: angular (rotaional) kinemaics v = rw. Kinemaic relaionships: see table 5. 1 (p. 165) a = r . - put on cheat sheet: rotaional dynamcs. Newton"s second law connects forces with acceleraion : = : work-energy theorem. For bodies that are both rotaing and moving linearly. *remember how we derived newt"s 2nd law in rotaional dynamics Useful since if you ind the ime rate of change of this angular momentum And make a big assumpion that the rotaional ineria is constant then: dl/dt = i(dw/dt) i = therefore: dl/dt = ext if = 0, then dl/dt = 0. Ex: increase to maintain balance skater doing piruouet; to balance that equanion, if they bring arms in, i is reduced, so w must. ** if your x and y components are all zero, you can place your rotational axis anywhere! (set it at where the most complicated, in terms of number of forces, spot is)
